


The Electric Medic

by LullabiesCradle



Category: Naruto
Genre: Fluff, Maybe a tiny bit of wish fullfillment tho, No self-insert, Protective Siblings, Smart!OC, Will add tags as I go, i have no clue what i am doing, no reincarnation
Language: English
Status: In-Progress
Published: 2021-03-12
Updated: 2021-03-12
Packaged: 2021-03-19 07:00:48
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 9,110
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29995632
Author URL: https://archiveofourown.org/users/LullabiesCradle/pseuds/LullabiesCradle
Summary: In the canon universe, we never found out what happened to the Hatake Matriarch. What if she had died giving birth to a baby girl? When Sakumo killed himself, Kakashi was left alone and closed himself off to the world. What would have happened if had a family member left? Meet Mistuko, the younger sister of the copy-nin.
Comments: 1
Kudos: 7





	1. Introductions.

Mitsuko has had such a long day. She’s hiding in a stairwell for a few minutes to take a breather, pulling her long silver hair back into a proper ponytail since half of it fell out in the chaos. She knew it was important work, and she was a fairly good medic for her age, but it was still so exhausting to be surrounded by so many buzzing people. 

Working in the Konoha hospital was almost always busy, being a ninja village and all, but this was a bit further than normal. There was a border patrol gone wrong, and they were almost double their usual workload. Mitsuko would have been only the errand girl a few months ago, limited to grabbing supplies and running orders and notes to various medical personnel.

“Mitsuko-chan! I need more bandages and saline over here!” “Someone bring more epinephrine, he’s flatlining!” “CHIBI-CHAN, hurry up! I asked for the portable EKG’s like ten minutes ago, are you even trying??” 

Yeah, Mitsuko does not miss those days. Instead, after graduating the Academy pretty early with the purpose of being a medic in training rather than joining the frontline fighters, she instead was placed in the thick of the triage and left to try to heal superficial traumas. Some stab wounds, quite a few slit tendons and slashed muscle groups. She left the more complicated impalements and blunt force head traumas for the more experienced medics in the group. It’s quite a bit of responsibility for a six year old, no matter how mature.

Things had been so busy with the Third War in its fourth year. It feels like it was a lifetime ago when it started. It may have well been one, the way life had been before and after. Both her and Nii-chan had changed so much. It came with the territory of losing your parents young, she guessed. 

She had spent the morning bent over various shinobi and kunoichi, using her modified Mystical Palm jutsu to close any open wounds. While she wasn’t the best at internal medicine or diagnostics, she was slowly making progress on having her own original iryo-ninjutsu. Having a raiton chakra nature came in handy sometimes. She at one point was trying to heal a woman's leg, but the wound would not stop reopening. She had clamped her glowing, slightly sparking hand onto the woman's leg, but the six year old wasn’t the physically strongest still being a small child. Mitsuko could feel her eyes watering on reflex, as her default reaction was still crying when overwhelmed.

“Kunoichi-san, I need you to stay still please!” Mitsuko frantically pleaded. The Kunoichi continued to squirm, making it quite a bit more difficult to stop the bleeding of the slash on her calf. It looked like whoever she had been fighting aimed for the Achilles tendon a bit lower down. The woman was lucky they missed, she wouldn’t have been able to walk had they hit their target. Mitsuko took a moment to be proud of herself for speaking up for once, normally too shy to say anything that could seem like a complaint. At least this patient wasn’t trying to make things more difficult on purpose, unlike a certain sibling of hers. She always had to scold her Nii-chan to get him to let her patch him up after a mission.

“Hai, Hai, I know! But it still tickles, I can’t help it chibi-chan!” The woman forced out between her betrayed giggles. She looked very unhappy with her body's reaction to the Raiton, clearly trying her best to stay still and failing all the same. Mitsuko appreciated the effort, the nickname a bit less.

She was told people call her that because she was a cute kid, her big blue eyes and chubby cheeks doing her no favors. It was hard to feel like she was an actual kunoichi when it seemed like nobody else really thought it. She found if she wore her hair in a plain ponytail or bun instead of her normal twin braids, people took her a bit more seriously. Not much, but some.

After a good ten minute struggle to stop the wound from reopening every time the woman moved before finally being able to close it, Mitsuko was allowed a five minute break before her next patient. Thankfully, most of the patients from the border patrol gone wrong had been taken care of by this point, leaving those left who either had training injuries or needed post-mission checkups. Sometimes both. She practically specialized in quickly treating minor injuries, with how she had come up with her modified Mystical Palm jutsu.

When the body heals a wound naturally, a stab wound for example, it requires a certain amount of energy to be able to regenerate the damaged tissue. Normally, it would take that energy from either calories eaten, fat cells, or muscle groups. It also was only able to work slowly, due to the time and effort it took to convert all of it into a usable form, but also due to the amount of heat formed when creating these new cells.

However, when using the Mystical Palm jutsu, the medics' pure spiritual chakra was able to replace the needed energy. The medics were able to encourage the regen rate of the damaged tissue by giving purified spiritual chakra, replacing the energy needed from other sources. It had to be done slowly though, as using too much at once could overwhelm the patient's chakra coils to the point of stressing them. If the patient's chakra coils were put under too much pressure, they could easily burst leaving the patient incapable of manipulating their stores ever again.

What Mitsuko had found, after extensive research and experimenting under the watchful eye of an older medic, was that if she didn’t use pure spiritual chakra and instead let in just the right amount of Raiton she could enhance the rate of regen even further. 

She had the theory it was because Raiton was capable of transferring more usable energy to injured cells, ie; wasting less energy in the process than purified chakra while not creating excess heat, but if you used too much it would cause the cells to overheat from working too fast, which is what stressed a patient's coils. A patient’s chakra coils bursting normally happened when the synapses where the chakra pathway of the body intertwined with the central nervous system were ‘burnt out’, losing any control of the release of chakra from nearby tenketsu points. So, if you were able to have enough control to keep a steady ratio while monitoring the regen carefully, she could almost double the normal healing speed.

At least, that's what she thinks is happening. Mitsuko doesn’t really have the most self confidence, and especially when it comes to her own skills. She can’t really be sure without more extensive studies on it, but is too shy to even think of asking for help. So she works on it by herself, which is her preferred way to train, honestly. The only person she really feels comfortable asking for help from is her Nii-chan, who thankfully almost always was able to make time for her if asked. She never understood the rumors about how little he cares about his fellow Konoha-nin, but maybe it was a bit of hero worship for her last living relative.

When her mother had given birth to Mistuko, it was a month or two earlier than expected. Their mother hadn’t lived long past that, her brother spending the first few years of Mitsuko’s life anywhere she wasn’t. She wasn’t sure if he blamed her for their mother dying, she knew she did though. It had been one of the things that had started her on the path of learning about medicine. Not to mention the fact that since she was born early, and was a fragile child because of that, she would never be able to be a frontline fighter. She got sick rather easily, with frequent issues with her lungs. Not to mention she would most likely always be on the smaller side, a few inches shorter compared to other children her age. So Mitsuko started training the day she learned about what happened to their mother, intent on becoming the best medic possible even, if it was just chakra control for the moment.

The thing that had both brought the siblings together and shattered their world was Tou-san committing suicide. Mitsuko had been home, sleeping in for once when she normally would have been at a training ground by then. Just because she wasn’t a super prodigy like her Nii-chan didn’t mean she couldn’t work hard. She also knew that you needed to take breaks every once in a while, to avoid burnout. She was peacefully dozing in her bed, when there was some odd noise in the living room that woke her up. A mix of the loud thud of something dropping to the ground, something dripping, and the gasping sounds of pain that had Mitsuko fully awake in seconds. Sprinting to the living room, she found her Tou-san unresponsive on the floor, a sword through his middle.

Being a terribly small child with only the slightest grasp on emergency medicine, she of course failed to save him. She was three, with the only thing she knew to do was stop bleeding. There wasn’t a way she could have saved him, but she didn’t know that. All Mistuko knew was that her Tou-san was bleeding and she couldn’t get him to wake up. She didn’t know what to do about the sword impaling her father, or the way his breath had been getting more ragged and strained by the second. It took less than two minutes for it to stop all together. She couldn’t do anything but cry quietly while clutching Tou-san’s hand.

Mitsuko knew her father was dead when she couldn’t feel him buzzing anymore. All people buzzed in some way, she could normally guess where people were based on it. Her Tou-san once told her that the buzzing was chakra, which was in all living people. She had lit up like the sun when her Tou-san told her she was a sensor, something special. But was she really that special if she had let her father bleed out while she did nothing but cry? If he didn’t buzz anymore, that she no longer could hear anything at all from him anymore, doesn’t that mean he’s dead?

Mitsuko spent the next few hours catatonic, sitting on the ground next to Tou-san, still holding on to his hand hoping he would squeeze hers back like he always did when she was upset. It wasn’t until her Nii-chan came home from the Academy and found the two of them that Mitsuko did more than stare at Tou-sans still form. That was the day the both of them lost the innocence of childhood. Her brother graduated early, with the intent of becoming a legal adult. It didn’t matter he was only six, if you had the hitai-ate to show, you were a legal adult in the eyes of the village.

He did this so they wouldn’t get separated, Mitsuko would have been sent to an orphanage while her Nii-chan would be living in a student-apartment. When he realized that Mitsuko was the only person he had left, he went from emotionally and physically distant to her awkward but trying Nii-chan. It was just them against the world, and he didn’t want to lose his last family member. As long as he was a legal adult, he would be allowed to be Mitsuko’s guardian, keeping the siblings together. He wasn’t the perfect older brother, but he loved her and tried his best so Mitsuko loved back him all the same. 

So Mitsuko tried to help too. When it finally came time for her to attend the Academy, she worked her hardest to progress as fast as possible. While she had been planning on not graduating early at first, she knew it would make her Nii-chan's life easier. She would be a legal adult as well, along with being able to earn small mission pay to supplement their household income. It was expensive being a new shinobi or kunoichi. The grocery bill alone could get pricey, needing large amounts of food for the growing children. Mitsuko had learned to cook to avoid having only take out, her brother was many things but not a talented cook. She found she enjoyed making bento’s for both of them, tending to make onigiri pandas and hotdog octopi. They were a bit cutesy, but her Nii-chan didn’t seem to mind too much. After demonstrating to her teachers where she actually was in her progress, since she had been trying to hide it to avoid the attention her brother got as a prodigy too, it wasn’t too difficult to get bumped up to the graduating class. It helped that their family had a history of producing geniuses. 

A loud buzzing broke her from her thoughts, she hadn’t realized how long she had been hiding in the stairwell and from the agitated chakra of one Nagano Etsuko, the current Lead Medic of the ER, Mistuko could tell she was needed. Etsuko-san, as she insisted Mitsuko call her by her first name, was a rather brusque woman who still had a soft spot. She wasn’t the most feminine or dainty, with a bit a potty-mouth too. She was in her early twenties, short and strong and a somewhat scary kunoichi. The woman insisted her nindo consisted of “Do no harm, but take no shit.” Mitsuko was intimidated by her sometimes, but still thought highly of her.

Mitsuko takes a deep breath, before exiting the stairwell and navigating her way back. She can still hear some commotion echoing down the halls, guessing that it was still busy but with only the more complicated injuries left. Etsuko-san tracks her down the moment Mitsuko is within her sensing range. 

“Mistu-chan! I need you!.” The woman calls out, power-walking towards her. Her light-brown curly hair sways behind her at the movement. “The shit-show of the border patrol has mostly been patched up, but we don’t have the medic’s to spare for the smaller injuries.” Etsuko-san dumps a pile of patient files in the young girl's arms who swayed at the weight, clearly intending for her to be the one to do it. While Mitsuko had only been an official medic in training for a few months, it was clear the stress of the war was stretching medic-nin too thin. The fact that a six year old was being put in charge of patients, them being smaller training injuries aside, showed the strain the hospital was under. 

“I, um, don’t think I am quite ready for this, Etsuko-san!” Mitsuko managed to squeak out, clearly starting to panic. “I only graduated a few months ago! I had thought medics-in-training would only do solo appointments after a few years!” The young girl's eyes started burning, she just knew that she was moments away from crying. That wouldn’t do her any favors in earning her patients respect, as it was already hard enough. Why did she have to have crying be her default response to stress? She wished she had Nii-chan’s poker face at times, how he was able to keep his cool through everything.

Etsuko-san shook her head quickly, already turning back around to get back to work. She called over her shoulder as she went, “You were an early graduate for a reason, Mitsu-chan. I know you can handle these, and we need all the help we can get!” The woman picked up speed, until she had rounded the corner again. The young girl let out a quiet sigh, since even when frustrated she couldn’t bring herself to make too much noise. 

Etsuko-san has too much faith in me, what if I mess up?? I don’t want to be the reason someone doesn’t get to go home to their families! I don’t think I am ready for this. Mitsuko thought frantically. She had already been making her way to the exam rooms, for her first patients, but she was slowly getting more anxious over the thought of failing. The walk over felt like an eternity, until she was just outside the room of her first solo patient. Mitsuko takes a deep breath, braces herself, and then opens the doors. The first thing she notices is the rather noisy argument that two of the rooms occupants were having. Maybe a Genin team? They both only look a few years older than me, maybe they are still trying to get along? The young girl watched from the doorway for a few more moments, curious when they would notice her.

“This is Bakashi’s fault, not mine! It’s not like I chose to break my arm!” yelled out a boy. He had short dark hair and annoyingly bright orange goggles. Mitsuko wondered how he managed to see anything through them. He also sounded a bit petulant, clearly upset about their missing third teammate.

A young girl, presumably the token Kunoichi of the team, continued to scold him. “I don’t care, you still have to be more aware of your actions! Imagine what could have happened if Minato-sensei hadn’t caught you in time?” She was giving him a look that was a mix of “I am disappointed in you” and anxious worry. Mitsuko couldn’t help but notice the purple face tattoos the girl had, it looked nice against her pale skin and framed with dark brown hair.

The third and last occupant of the room was a blond teenager falling asleep in the corner. Mitsuko felt sorry for him, his genin team must be a handful if he was managing to sleep through this noise. If the hospital didn’t have silencing seals on exam rooms for privacy, she was sure the children arguing could have been heard across the building.

You can do this Mitsu! Fake it til you make it! She thought to herself, before speaking with false confidence to get their attention. 

“Good afternoon everyone, who will I be seeing today?” Mitsuko asked politely. Even though it was obvious that her patient would be the boy clutching his left arm to his chest, she didn’t want to assume. She immediately felt the weight of three different sets of eyes. 

“Eh? What’s a brat doing in here?” The boy blurted out, seemingly unthinking. Mitsuko immediately deflated, any chance at trying to be confident washed away with that comment. His teammate looked promptly horrified at his manners, having already spotted the Hitai-ate Mitsuko wears around her neck. It was their teacher that broke the awkward silence.

“Obito, be polite. She earned her Hitai-ate, don’t be rude.” The blond chided his student, before turning to the medic in training. Mitsuko hadn’t even noticed that he had been awake the entire time, and he had a knowing look in his eye when he turned to her. “My student fell wrong during a spar with his teammate, I’m pretty sure he broke his arm from the noise it made when he landed.” The blond sounded both resigned and worried relaying this info, resigned he had trouble makers for students but worried all the same. Supports my theory of a relatively new team, at least. Mitsuko mused to herself.

Mitsuko nodded at the shinobi, before turning to the boy. His face had a flush to it, but she wasn’t sure if it was from embarrassment at his blunder or from pain. Either way, she pretended not to notice. Mitsuko started by asking the boy to move his arm in a few different motions, watching his reaction closely. From the way he winced at certain positions, she had no doubt he injured at least something. She spoke again, turning to the boy. “Genin-san, would you please remove your jacket?” The boy nodded slowly, clearly unsure why.  
With just his t-shirt left, Mistuko was able to begin the process of healing him. When her palms lit up, lightly sparking from her modified Mystical Palm, she could feel the gaze of their teacher sharpening. She hoped it was just because she was younger than most who knew this particular jutsu. It required an insane amount of chakra control after all, that most wouldn’t get close to until they were teenagers. Given that Mitsuko was currently six, she could understand why it must seem odd.

What really made her uncomfortable, was the way the two genin reacted.

“Wow! I didn’t know that medics could start so young!” The boy, Obito according to his teacher, sounded gobsmacked. “I didn’t even know so many people graduate early, I thought Bakashi was an outlier.” Obito eyed her hitai-ate, grumbling under his breath about their missing teammate. She didn’t even blink at the name, too focused on trying to heal his arm. The kunoichi was sending shocked and slightly envious glances at the jutsu the younger girl was using. The way both of them looked at Mitsuko made her want to squirm and fidget. She instead tried to focus on her work.

She could feel the cracks of a fracture along his Ulna and Radius, the pattern it followed made her think he had tried to catch himself, but the awkward placement of his weight on his arm and wrist caused them to fracture. She also thinks he might have sprained his wrist from the decent amount of swelling and bruising it had too. Her attention fully on her healing, stubbornly ignoring the conversation around her, led her to miss the door opening at first.

When the boy she was healing started to rant at their formerly missing teammate, she finally looked up having just finished. Just to see her Nii-chan in the doorway, who was surprised to see her too. Not that he showed it much, she only could see it because they were so close.

“Nii-chan!” She called out happily, going from shy and quiet to slightly louder and energetic. After the mess of a morning she had, she was very excited to see her older brother. She felt the smile blooming across her face. The three other occupants of the room had differing reactions. Their teacher smiled, clearly having recognized who she was before Kakashi-nii had joined them. His kunoichi teammate let out a quiet gasp of surprise. But Obito managed to get even louder, blurting out, “Since when does the teme have a sister!?” 

Mitsuko barely registered all of this, having dove to her brother for a much needed hug after the stressful morning. Kakashi-nii didn’t seem to mind too much, even if he was flustered at the commotion. He just let out a sigh, wrapping his arms around his younger sister a bit awkwardly. He doesn't give perfect hugs, but he’s trying. Mitsuko thought to herself. She was so grateful she had her Nii-chan, and she didn’t know what she would do without him.

Kakashi-nii clearly wasn’t as enthusiastic in his response to his teammate. “Dobe, I have had a sister the entire time, it’s not like she was born yesterday. Just because I don’t talk about her often,” His complaints turned into quiet grumbles. Her brother knew how much she hated conflict, she got anxious rather easily and negative emotions make people buzz even louder. She appreciated that he tried to keep any conflicts away from her, even if it was just a petty argument with a teammate.

Their teacher cut in, both to move the conversation forward and to stop their bickering. “It’s about time we met Kakashi’s imouto!” The blond, who Mitsuko realized must be Kakashi-niis sensei Minato, who then went on to tease her brother. “I was starting to wonder if we ever would, looks like it took some outside intervention.” Her brother's sensei seemed to be pleasantly surprised, but his teammates were shocked. Mistuko pulled herself off her brother, but was still latching onto Nii-chan’s hand like normal. She wondered why Kakashi-nii’s teammates were giving their clasped hands weird looks, but ignored them.

“Nii-chan, I have a few more patients I have to see before my shift is over, but after could we go out for ramen?” She sent a bright smile at her brother. There was a stand near Hokage tower that had such good Tonkatsu, and she desperately craved some comfort food. Kakashi-nii just sighed, and quietly nodded his agreement.

That seemed to shock the others the most, including their sensei. Was it really that odd for her brother to agree to going out for dinner? 

Kakashi-nii firmly ignored their actions, quietly asking “Does your shift end at the same time as usual, Imouto?” She nodded happily as reply. “We can meet there soon then, you have more work to do I’m guessing from the way you are hiding out here longer than necessary.” Kakashi-nii gave her a knowing look, as Mitsuko had a bad habit of procrastinating anything that made her nervous. 

She gave him a small pout, her big blue eyes watering slightly. She knew the expression was particularly effective in getting her way with people. As always, it seemed like her Nii-chan was the only person who was able to resist it. He gave a small snort, before wryly saying, “Nice try Mitsu-chan, add in a bit of a wobbly lip next time.” He was clearly unaffected, as usual. She gave him an honest pout this time, before leaving the exam room they were all in. 

“Meet you there in an hour Nii-chan!” She called over her shoulder, already hurrying off to finish her work. She didn’t bother with a proper goodbye, as her brother knew she would be rushing now to get things over with. Nothing was going to stand between her and a bowl of heavenly Tonkatsu Ramen after the day she had, even if it meant she had to do more solo sessions. 

If it wasn’t for the privacy seals in each exam room, she would have heard the commotion that came from his teammates' reaction to the change in personality Mistuko’s brother had around her. Not that she really noticed that to begin with, the hero-worship she had for her older brother made her a bit blind to those things honestly.

Years laters, Mitsuko would think back on this interaction with fondness. There probably were better ways to meet her brothers Team 7, but she wouldn’t change it for the world. It was the start of a new chapter looking back, and at least it started well. They wouldn’t have as much luck later on.


	2. A Big Brother's Point of View

**Summary for the Chapter:**

> Kakakshi hasn't always been a good brother, but he is sure as hell trying now.

Chapter Two

Kakashi sat at the bar of Ichiraku's Ramen, eating quietly while his little sister rambled about her day. It had been quite busy today, but from the way Mitsuko talked about it, it sounds like she was able to handle it fine. He worried for her often, that his shy sweet little sister would be taken advantage of, that he would lose her like their parents.

He wasn’t very happy when she had been brought home as a newborn. Okaa-san had been talking about having a younger sibling for months, about how to be a good big brother. He certainly wasn’t a very good one at first, as he had intially blamed his little sister for being the reason Okaa-san hadn’t come home with her. 

Tou-san never really talked about what happened much, giving only the basic info to both children when they asked. Mitsuko was born too early, through no fault of her own. Their mother lived just long enough to bring her into the world, leaving it herself minutes after. Mitsuko almost joined her, having been born too early had some serious consequences on her. The medics said that she would most likely never be able to become a ninja, she would always be on the smaller side and most likely would be medically fragile.

Kakashi was a mix of resentful and ashamed of his younger sister at first. He refused to spend more time around her than needed, half of him thinking she was the reason their mother was dead and the other half too scared to get attached in case Mitsuko joined their mother. Tou-san had issues taking care of the baby girl, grieving the loss of his wife and then dealing with the fallout of his failed mission just a few months later. Sometimes Kakashi would be left in charge of her, and even then he tried to keep his distance.

His baby sister still grew on him regardless.

It had started with her first word, if he was to be honest. Tou-san had a mission over the weekend, and Kakashi had been expected to take care of her during that time. Never mind the fact he was a child himself. He forgets what age they were exactly, only that it was a bit before Mitsuko’s first birthday. It had been the middle of the night, both of them had been asleep for most of it. 

Then Mitsuko had a nightmare. He never found out what about, only that it was something scary. He had woken up the moment he realized she was softly crying. She really isn't ever noisy, even when she was a newborn. Their bedrooms were straight across from each other, and with both doors open Kakashi was able to pick out the sounds of her soft sobs in his sleep.

He had been surprised at the concern he felt, reasoned with himself that it’s only because he was assigned babysitting duty by Tou-san and didn’t want to disappoint their father. The young boy crawled out of bed, and shuffled to his sister’s crib. The window in her room only gave enough light for him to make out the shape of his baby sister, and the fact she was truly upset. He knew babies cried about all sorts of things, if they needed clean diapers, if they were hungry, if they were bored. He had been surprised to realize Mitsuko wasn’t crying over any of those. 

When she realized Kakashi was in the room with her, the infant made an effort trying to climb the bars of her crib to reach him. Kakashi tried to pretend he didn’t know what she wanted. He really really didn’t want to hold her. That changed promptly when he realized her normal babbling was understandable for the first time. Well, part of it. 

It took him a moment to decipher it, but he felt a wave of guilt when it clicked. Kashi. She had been trying to say his name, to try and get his attention. Her first word had been his own name, the brother that tried to ignore her existence, had blamed her for something she had no control over. The infant didn’t care about any of that, just that she wanted her brother. Some cold part deep inside him thawed a little at that. Didn’t quite melt, but he was warming up to her.

He had picked her up, the first time that had been willing and non-essential, and she immediately latched onto him in a hug. Her face was dirty with snot and sticky half-dried tears, but he couldn’t care less. They sat on the floor of her nursery, her cuddling up to her older brother reveling in the comfort while he was reconsidering his opinion of her. 

She may never be a frontline fighter, much less a ninja at all. She would most likely be a sickly, weak child. He had written her off at the start. Had blamed her for things she was not at fault for. But she still loved him regardless, enough that her very first word was his name. He needed to be a better big brother, since it was clear she would be a loving little sister.

His Tou-san looked strangely relieved when Kakashi told him about her first word when he came home. Kakashi had thought at the time he was relieved that the boy was finally bonding with his sister. 

The next thing that affected his view of her was the day she found out about their mother. She must have been around a year and a half at this point. She was a curious little thing, always asking questions. Mitsuko didn’t have the best grasp on actually talking, but she understood what people said mostly ok. Her favorite word at the time had been “Why?” (He secretly enjoyed that fact that her apparent second favorite was Kashi-nii.)

They had been at the public playground, Tou-san asking Kakashi to take her for a bit so he could sleep after a rough mission. Kakahsi didn’t know at the time how bad of a mission it was, but looking back years later he would regret not checking on his father more. Mitsuko had been sitting next to him, both of them relaxing in the sunlight, resting on soft grass. In the distance, there was a set of parents pushing their child on a swing. His baby sister watched them closely, before turning to him to ask “Why?”.

“Why what, Mitsuko-chan?” He looked down at the tiny form of his sister. She didn’t seem to be looking at the kid on the swing, but the parents pushing him. Or more specifically, the mother off to the side.  
“Why only Tou-san?” She had tried to ask. She didn’t have the best grammar or vocabulary, but after a moment he understood what she meant. Wasn’t she a bit young to be wondering why they only had a father? He really should leave this to Tou-san to answer, but being a good big brother involves answering the younger siblings questions.

“You want to know what happened to Okaa-san?” He asked, watching as she digested the new word before nodding. He sighed, and tried to think how to phrase it best. “When you were still in Okaa-san’s tummy, she got very sick. She wanted you very much, and was looking forward to meeting you.” He took a breath, and tried to phrase it gently. “Okaa-san died making sure you would get here okay.”

Mistuko gave him a confused head tilt, clearly only understanding part of that explanation. “Okaa-san dead?”

Kakashi flinched at her blunt statement. He knows she wasn’t trying to be rude, that she was a tiny child with no concept of death, but couldn’t quite keep a neutral reaction to the statement. She definitely noticed she had upset him though. 

“What dead?” She asked hesitantly, clearly upset herself that she made her brother sad. Kakashi had to take a deep breath. He was too young for this, trying to explain the concept of death to a toddler asking why they didn’t have a mother. He was already rather jaded for a four year old, even if he would be five and joining the academy soon.

“Dead, is when something stops living. Remember our house plant we forgot to water? How it turned brown and crispy, and wouldn’t ever be able to fix itself? It was dead. When a person dies, their body stops working anymore. They won’t be able to talk, or play with you. You won’t be able to see them again.”

It was a wordy explanation for a two year old, even if none of the words were very complex. It was very easy to see she had started to understand what he meant. The tears she was sniffling back were at least very obvious. “No fix?” She mumbled out, it took kakashi a moment to understand she was asking why they couldn’t make her better. 

He let out a shaky breath, before telling her, “There are ninja who are able to fix people sometimes, but there will always be times that not even the best medic can save someone. Okaa-san wanted you very much, and made sure the medics were trying to help you more, as there weren't enough people to help both of you.” He quickly grew alarmed at the increased pace of his little sister's tears.

In the quietest voice he had heard from her, she whispered out “Am bad?”

Kakashi flinched at that, realizing his sister had grasped the implication that Okaa-san had died because of her, even if it wasn’t really Mitsuko’s fault. Reaching out after a moment of hesitation, he pulled her into a hug. Her tiny hands curled into his shirt, tucking her face into the crook of his neck. He wasn’t very good at messy emotions, but part of being a good big brother is making sure the younger sibling is ok, so he was trying his best. He tried to comfort her.

“Okaa-san loved you very very much. She wanted you to be ok more than anything. She made the choice that medics would focus on you before her. The hospital is a very busy place, and there aren’t always enough medics to help everyone.” Which was a bit of an understatement considering the current condition of the war, but he didn’t need to tell her that.

Mitsuko curled into him for a bit still sniffling, the two of them sitting quietly while she thought. If the world was a more literal place, there would be steam coming out her ears from how hard she was thinking her current train of thought. He wondered what it was. 

She pulled her head back to look him straight in the eyes to ask, “I help?”

Kakashi didn’t get what she meant. “Help with what, imouto?”

She gave him a determined look, declaring “I help no more dead?” It clicked a few seconds later. His grey eyes widened a bit.

“You want to become a medic?” He was both surprised and not surprised at this statement from his baby sister. It was just like her to care so much, even if she never got to the chance to meet Okaa-san. The story clearly had enough impact that she wanted to help. He swallowed roughly before continuing. “Being a medic is very hard, you would have to work really hard on your chakra control and study even harder.” 

The tiny girl looked even more determined at this, nodding seriously in a way that seemed more cute than truly serious. “Kashi-nii, help?” She was asking for his help to become a ninja? To become a medic? He couldn’t help but smile a bit at that, she always seems to think he must know everything.

“I haven’t even started the Academy yet, Imouto. I think that would be a better question for Tou-san.” He may have started chakra control exercises already, but Tou-san really should be the one to get her started. Not to mention her being so young, it would hurt more than help at this point. 

She pouted at that, but stopped the questions for the moment. She didn’t completely let go of him the rest of the day, tightly gripping his hand in a way that showed she was still a bit upset at what she had been told.

The thing that really sealed it for him though, was the worst day of their lives. It was almost the end of the school year, and he was excited to tell his father that the teachers wanted him to join the graduating class. He had felt so proud and couldn’t wait to tell his Tou-san. All of that was wiped from his mind when he made it home. He was able to smell the copper tang of blood before he even opened the door.  
Kakashi was met with the sight of his father dead on the floor, a sword through his middle, and his baby sister shaking and sobbing silently. She had a deathgrip on Tou-sans hand, but didn’t seem to be all that aware. He felt numb himself, looking down at the still form of their remaining parent. What had been their remaining parent. 

Why? Why would Tou-san… Kakashi knew his father had been harassed unendingly from their fellow villagers, blaming Tou-san for the war, but why would he leave them? Kakashi couldn’t do anything but stare for the longest time. It could have been seconds, minutes, or hours and he wouldn’t have been able to tell. He just continued to stare at the dead body of their father. What finally broke him out of it was Mitsuko realizing her brother had come home, that she wasn’t completely alone. She had jumped him, clutching on to him in the tightest hug she had ever given.

Almost a mirror of their conversation from a year ago, the three year old told him, “I tried to help.” She had been stuck on the idea of being a medic, insisting that she wanted to be able to make sure everyone would be ok. She wanted to be able to make sure people were able to stay with their families, unlike Okaa-san. 

She had clearly thought the same thing about Tou-san, considering how blood stained her hands and clothes, probably from trying to help but not being able to do anything. 

He still felt numb, but not quite shattered when he tried to comfort her. He picked up his baby sister, and walked them out of the house, if only to sit on the porch away from Tou-san. He certainly felt cracked, but he didn’t shatter. Mitsu-chan needed him, that was the only reason he hadn’t died inside completely at the fact Tou-san left them. 

The only person he had left in the world was Mitsuko, his innocent baby sister. He couldn’t leave her alone now, if he didn’t need to take care of her he would have been catatonic on the floor until someone found them. But she needed her Kashi-nii, so he tried to hold himself together. Apparently, holding a crying toddler covered in blood was enough to get the attention of some adults, though Kakashi doesn’t remember much past that.

The only thing that really stuck with him was realizing she was all he had left, and it was up to him to make sure she would be ok. That was the moment that Mitsuko was cemented as the most important person in his life, that he needed to be the older brother he had failed at being so far. He wasn’t sure what would have happened if he had been completely alone. It was a miracle he hadn’t become hateful to everything, only a bit cold and jaded. 

Watching his imouto ramble about her busy day as a medic in training, about how she had made progress with her Raiton Mystical Palm modification, and how she had gotten better at healing with it. He hoped she knew he was proud of her, even if wasn’t able to say it out loud. He still wasn’t any good with messy emotions.

She worked so hard to master her chakra. Their family normally had generous stores, Kakashi himself having a decent amount above average. Mitsuko had been born too early though, her growth stunted. She would never be able to be a frontline ninja. She was still too slight in form to be any good with taijutsu, she gets knocked over sometimes on too windy days.

But she would work herself into the ground if it meant she would be able to help someone up one day. She was just as smart as he was, if not more with the amount of time she spent reading medical text-books instead of heavy physical training. The fact that she had been able to even use Mystical Palm before she reached double digits? She was a prodigy the way he was. Spent just as little time at the Academy as he did.

He had tried to tell her that she shouldn’t rush, that she should take all the time needed to learn. Mitsuko insisted on graduating early when it was offered, having been noticed using Mystical Palm by one of the teachers. She had learned it through a scroll, too shy to ask for help. So when a retired medic who taught the older classes saw her using it trying to heal a scrape on a classmate, she was promptly snatched up and placed in the graduating class. She wasn’t to be placed on a genin team either, she was offered a spot in the training programs for medics.

It was comforting, in a way, to know she wouldn’t ever be on the frontlines. Kakashi had seen what war was like when out on missions with Minato-sensei. Had seen how his teammates changed after witnessing it. He never wanted his baby sister to be in the thick of this mess, he knew she wasn’t strong enough to survive long. She was still so small, even if she was growing by the day. She would be determined and stubborn enough to try, but she just wasn’t physically strong enough. He thanked kami that medics were a rare resource for ninja, that weren’t treated as disposable as others.

He was pulled out of his thoughts when two more people joined them at the ramen stand. He felt the barest upturn of his lips when he noticed who.

“Minato-sensei, what are you doing here?”

The older ninja gave him a cheery smile, as he and Kushina settled down next to the siblings. “You can’t be serious Kakashi-kun! I’ve spent the past two years waiting to meet your family, I didn’t have to wait nearly as long for your teammates.” There was also the fact he has only had the teammates for a few months, and both were orphans too. Minato only met with Obito's grandfather and the Orphan Matron that Rin called Kaa-san

Both of them knew it wasn’t as big of a deal as he was making it be, teasing him more about how long Kakashi had his mouth shut about his Imouto. She wasn’t very fond of attention, preferring to stay in the background of things. So when people started paying attention to him, he kept quiet hoping to avoid having the light shined on him and wouldn't spread to her too.

He did enjoy his teammates expressions earlier today. The look of shock, and the way they acted like the world was ending because he showed any positive emotions. He had to wonder if they assumed he didn’t have any though, if they were that surprised.

“Oi! Kashi-kun, aren’t you going to introduce us?” Kushina gave him a wicked grin, clearly enjoying the situation. His sister had been sitting quietly, shifting subtly behind him. She was always nervous around strangers, but he thought it was better than the alternative of too trusting. Kushina continued gleefully, “It’s rude to keep a lady waiting, ya know?”

Kakashi rolled his eyes, before turning to his sister. “Imouto, this is my Sensei, Minato Namikaze and his partner Kushina Uzumaki.” He gave a monotone, lacklustre introduction, but Mitsu-chan still lit up. She clearly recognized Minato-sensei back at the hospital, but he was surprised at how excited she was about Kushina. He wonders where that came from.

“Sensei, Kushina-san, this is my younger sister, Mitsuko Hatake.” His younger sister peeked out around his form, barely glancing on Sensei and focusing mostly on Kushina. Kakashi felt the tiniest bit upset at the hero-worship in her eyes, a look normally reserved for him. He has to wonder what got Mitsu-chan to look at Kushina like that. He got his answer surprisingly easily.

“You’re the Red Hot Habanero! Is it true you used seals to chain a stuck up shinobi to the Nidaime's head on hokage mountain? I heard it was ‘cause he said all kunoichi were good for was being medics.” His little sister practically gushed at the older Kunoichi.

What a rollercoaster of a statement, with how it started out he was worried he would have to save Mitsu-chan from getting pummelled by his sensei’s girlfriend. The woman’s face jumped from indignant anger at the name, to smug pride with a hint of embarrassment. It finally settled on confusion as the redhead was trying to work out the last part of the statement.

“Wait, aren’t you a medic? Aren’t you some sort of prodigy budding iryo-nin? Minato mentioned how you have made an effective modification to a jutsu too difficult for most full-grown medics.” The woman side-eyed her boyfriend, who was a bit of a nerd for jutsu-creation, even if it was one he wouldn’t be able to use.

Kakashi’s little sister flushed dark enough to match Kushina’s hair. She had never been one to handle praise well, she gets flustered rather easily. He wishes she would have a bit more confidence in herself, or at least her skill. 

“I might be a medic, but it’s not all I am good at. Kunoichi are medics more often than shinobi, so some boys, er, guys think that means all Kunoichi should be medics. Not everyone enjoys healing like I do.” Mitsuko gave a very cute pout as she said this, making her look more like a cute kid than a serious comrade. He tried to keep a neutral expression though, her catching onto his feelings on this won’t do any favors for the confidence.

Kushina had absolutely no issue doing the opposite.

The red head plucked his tiny sister off the stool, and proceeded to almost choke her with forceful physical affection. “You are just the tiniest, cutest creature I have seen in my life! Oh my goodness, how could Kashi-kun hide you from us!” The woman gave an impressively loud smack as she kissed Mitsu on the forehead. Kakashi watched her carefully, as Mitsuko normally didn’t react well with strangers to begin with, and this is quite a bit further than most people go the first time they meet. Much to his surprise, his sister seemed to enjoy the affection, smiling up at the woman. 

Is this just how she reacts when it’s someone she looks up to? I’m sure I’m still her favorite… I hope… Kakashi consoled himself, having never seen Mitsu-chan react so positively to someone that wasn’t him. He tried to act like he wasn’t bothered by it, but from the way Minato-sensei was snickering Kakashi knew he wasn’t doing a very good job.

His Sensei seemed to be enjoying the scene anyways. He’s been teaching Kakashi for two years by now, and this was the second time he had met Mitsuko. The first was an hour ago in the hospital exam room with the rest of their team. It was still the first few months having teammates too, Rin Nohara and Obito Uchiha being graduates of the most recent class. 

His team was an odd group that he didn’t know how to feel about. 

Minato-sensei has become something close to an older brother, someone Kakashi loves in a similar way to Mitsu-chan. Maybe not as strong, but it’s definitely familial love. Minato-sensei has been bugging him for a while meeting his sister, after seeing his packed bento’s for the first time. Kakashi can practically feel his face heating up at the memory.

Having to explain that the cutesy lunch was not from a girlfriend, fangirl, or something he made himself. Not that there was anything wrong with guys liking cutesy stuff, but it definitely was not the aesthetic for him. His sensei would not shut up about it until Kakashi admitted it was from his younger sister. Minato-sensei admitted later he knew the entire time, but had been enjoying teasing him from how he would turn red.

Not that it was much better than his teammates' reactions. The one time they managed to catch him during lunch time long enough to see the Onigiri panda his sister favored, with a tamagoyaki cut and placed like a heart. The assorted fruit cut in simple shapes like flowers and stars seemed to be the finishing touch that caused Obito to bug him about it every chance he got.

Kakashi tried to ignore the fact that Rin would give his bento a glare that was a cross of irritation and disappointment. She was a quiet fangirl at least, so practiced his daily denial of reality and pretended that she didn’t get jealous over the perceived threat that was actually Kakashi’s little sister. 

By the time Kakashi realized he had spaced out, dinner was already almost over. The sun was starting to go down, and he needed to get his sister and himself in bed. They may be mature, but they were still small children who needed the sleep to develop properly. Mitsuko had been falling asleep sitting up, leaning heavily against him. Kushina-san was cooing at her, claiming it to be ‘Just Precious!’. Kakashi gently shook his sister awake, “Mitsu-chan, time to wake up. We need to get home before it gets dark.” 

She gave a pathetic little whine, complaining that she didn’t want the day to end. She was still looking at Kushina with some hero-worship, clearly reluctant to leave before her and Sensei did.  
Kakashi tries bribing her, “Imouto, I’ll give you a piggy back ride, c’mon.” Kakashi struggled to stifle a yawn. 

Mitsuko still looked hesitant. Kushina decided to lend him a hand after realizing why the girl was behaving this way. “Mitsu-chan, we will need to meet up again soon sometime! No way am I letting you get away from me forever!” Kushina picked his sister up again, squeezing her in a way reminiscent of a stuffed animal. He was honestly surprised at how happy it made his sister.

“Hai Kushina-senpai!” She gave the woman a sleepy smile, clearly happy with that declaration. Looking up at her brother, hopeful big blue eyes making him relent before she even asks. His sister climbs onto his back, and once she feels secure and sure she won’t fall, she’s out like a light. Minato-sensei and his girlfriend apparently find the two of them adorable, Kushina not being the only one cooing for once. 

“Kashi-kun, make sure to get some sleep too!” Kushina gives him a cheeky grin. His sensei on the other hand tells him to be up early at their normal training grounds. The four head off in separate directions, the sun painting the sky as it sinks down the horizon. It was a good day, for it being when his sister finally met his team. 

He has a feeling Kushina was serious though, about not letting Mistu-chan get away forever. He could only hope she would be a good influence on his baby sister. There was a reason he avoided having her meet his team this long in the first place.

**Notes for the Chapter:**

> Have y'all ever noticed how Kakashi got a bit overprotective of Rin after Obito 'died'? If was placed in charge of a younger sibling after they lost both their parents, I just know he would be even worse. My headcanon was Kakashi really only got cold and cruel as a kid after Sakumo bit the dust. If he hadn't been left completely alone after a traumatizing event, I think it would also change how his personality changes too. Rather than cold ruthless "Shinobi rules!", maybe he would be Jaded and Cynical, but not cruel or hateful. That's my reasoning at least and I'm sticking to it. This chapter is dedicated to those three kudos and the one review. I underestimated all those authors who said "Reviews and Kudos are like drugs!"

**Author's Note:**

> I have no clue how to write my dudes, but I am gonna try. I think it would be fun to flesh out medical ninjustu, and most OC's for naruto fanfiction end up as frontline fighters, not enough stories about other types of ninja. While there will be a bit of wish fulfillment (I wanted a older brother growing up so bad), I will be trying to make Mitsuko her own person. She will be super smart, considering the family she came from it's not too big of a reach, but she will never really be a strong opponent in a fight. We will have to see where this goes.


End file.
